Wear-resistant layer on a component and process for the production thereof

ABSTRACT

A wear-resistant layer on a component which is exposed to a high wear loading has a material mixture comprising at least one metallic material in powder form and a non-metallic oxide-dissolving fluxing agent in powder form which by the addition of a resin-like non-corroding stable binding agent is converted into a form which is applied to the component by being spread or laid thereon, and fused.

BACKGROUND OF THE INVENTION

The invention relates to a wear-resistant layer on a component which isexposed to a high level of wear, and a process for the production ofsuch a layer.

Many processes are used for coating parts or workpieces, such as forexample thermal spraying, CVD, PVD and galvanic processes.

Processes are also known, in which the material for the coating isapplied by brushing in the form of a paste or in which it is applied asa strip. It will be appreciated that in that case they can only be fusedin position in a vacuum or under a reducing protective gas.

All those processes involve very high levels of cost, because of a highlevel of apparatus expenditure, and for that reason such coatingoperations can only be carried out in the workplaces which ale equippedfor that purpose.

Therefore, for producing simple and inexpensive mass-producedcomponents, it is necessary to find a process for applyingcorrosion-resistant and wear-resistant layers, which process makes itpossible to keep the costs of a protective coating as low as possible.

SUMMARY OF THE INVENTION

That object seen by the inventor is attained by the teachings of thepresent invention which; by virtue of the use of a material mass inpaste or strip form, which comprises metal powder, with or without oneor more hard substances, a fluxing agent and a resin-like binding agent,it is possible for the applied material to be fused in position, withouttaking into consideration the ambient atmosphere, for example in air orwith an autogenous flame or in a muffle furnace, without protective gas.

The present invention provides a wear-resistant layer on a componentwhich is exposed to a high wear loading, which comprises a materialmixture comprising at least one metallic material in powder form and anon-metallic oxide-dissolving fluxing agent in powder form which by theaddition of a resin-like non-corroding stable binding agent is convertedinto a form which is applied to the component by being laid or spreadthereon, and fused.

In addition, the present invention provides a process for the productionof a low-wear protective layer on a component which is exposed to highwear loading, which comprises mixing at least one metallic material inpowder form and a non-metallic oxide dissolving fluxing agent in powderform, and adding a resin-like non-corroding stable binding agent to thematerial mixture, whereafter said binding agent-containing materialmixture is spread on or laid on the component, and fused in position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Further advantages, features and details of the invention will be foundhereinbelow.

EXAMPLE 1

For the production of a self-sharpening blade cutting edge, a materialmass in paste form was applied to a steel plate using a brush, thematerial mass comprising a mixture of an Ni-Cr-B-Si-alloy powder with25% by weight of chromium, 0.2 to 2.0% by volume of fluxing agent and 4to 6% by volume of a water-soluble methacrylate. After drying andhardening that layer was fused with a flame.

After the fusing operation the coating produced in that way presented aclean and smooth surface which was distinguished by good corrosionresistance.

EXAMPLE 2

To produce the material mass in paste form, 0.1 to 1.5% by volume offluxing agent and 5 to 7% by volume of methacrylate were added to amaterial mass in paste form comprising a mixture which contained anNi-Cr-B-Si-alloy material and a tungsten carbide powder with a mixingratio of 50:50. Production of the coating on a wearing component waseffected as described in Example 1. The finished layer had a high levelof resistance to wear.

EXAMPLE 3

A coating was produced as in Example 1, using a material mass in pasteform comprising a mixture of an Ni-B-Si-alloy powder and chromiumborides in a mixing ratio of 70/30. Added to that mixture were 2.5 to4.5% by volume of fluxing agent and 3 to 10% by volume of awater-soluble methacrylate.

The coating produced in that way afforded good resistance to corrosionand wear.

EXAMPLE 4

A coating was to be applied to a tool subjected to intensivehigh-temperature wear loading. This Example involved applying to theloaded surface a material mass in strip form comprising a mixture of 20%by weight of an Ni-Cr-B-Si-alloy powder and 80% by weight of chromiumcarbide powder which were mixed with 2.2 to 5.1% by volume ofbenzine-soluble methacrylate and 1 to 3% by volume of fluxing agent. Thethick paste produced in that way was now rolled out to form a strip,dried and hardened. The strip was now applied to the part of theworkpiece to be coated, and fused in position in a muffle furnacewithout protective gas.

The coating produced in that way, with a layer thickness of 2 mm,exhibited good resistance to high-temperature wear.

EXAMPLE 5

Applied to the surface of a component which is to be in part providedwith a coating of a corrosion-resistant material was a material mass instrip form, which comprised a mixture of an Ni-Cr-B-Si-alloy powder witha chromium content of 16% by weight, 4 to 5% by volume of fluxing agentand 4 to 6% by volume of benzine-soluble methacrylate. An inductionsoldering installation was used for fusing in position the strip-formmaterial mass applied to the component.

The layer applied met the requirements made in regard to resistance tocorrosion.

EXAMPLE 6

The coating operation was carried out as described in Examples 4 and 5,with the difference that the mixture for the material mass in strip formcomprised a mixture of 50% by weight of an Ni-Cr-B-Si-alloy powder, andwith 50% by weight of a hard material mixture with 25% by weight oftungsten carbide and 75% by weight of chromium carbide, to which 4 to 6%by volume of fluxing agent and 3 to 5.5% by volume of benzine-solublemethacrylate were added.

The paste produced in that way was now rolled out and hardened. Usecorresponded to the manner of use described in Example 4.

I claim:
 1. A layer on a component which is exposed to a high wearloading, which comprises a material mixture comprising at least onemetallic material in powder form and a non-metallic oxide-dissolvingfluxing agent in powder form which by the addition of a non-corrodingwater-soluble stable binding agent is converted into a coatable pastefor application to the component by being laid or spread thereon, andfused to form a hardened, wear resistant coating on said componenthaving an exposed coating surface, the said metallic material being atleast one of a Ni-B-Si base alloy, an alloy on a Ni-Cr-B-Si base, and amixture of a Ni-B-Si alloy and a Ni-Cr-B-Si base alloy.
 2. A layeraccording to claim 1 wherein the material mixture includes as a bindingagent for the material mixture, salts of methacrylates.
 3. A layeraccording to claim 2 wherein the material mixture includesbenzene-soluble methacrylic acid esters as a binding agent for thematerial mixture.
 4. A layer according to claim 1 including apolyurethane resin as a binding agent for the material mixture.
 5. Alayer according to claim 1 including an amount of binding agent in thematerial mixture of below 16% by volume.
 6. A layer according to claim 5wherein the amount of binding agent in the material mixture is from 2 to8% by volume.
 7. A layer according to claim 1 wherein the fluxing agentis at least one of boron-oxygen compounds and boron-fluorine-oxygencompounds.
 8. A layer according to claim 1 wherein the proportion offluxing agent in the material mixture is between 0.5 and 20% by volume.9. A layer according to claim 8 wherein the proportion of fluxing agentin the material mixture is between 1 to 10% by volume.
 10. A layeraccording to claim 1 including the addition of hard substances to thematerial mixture in powder form wherein the proportion of hardsubstances in the material mass is between 20 and 90% by volume.
 11. Alayer according to claim 10 wherein the proportion of hard substances inthe material mass is below 80% by volume.
 12. A layer according to claim10 including carbides as the hard substance additives.
 13. A layeraccording to claim 10 including at least one of the following as hardsubstance additives, tungsten carbides, borides, silicides, andnitrides.
 14. A layer according to claim 10 including an addition ofcobalt.
 15. A process for the production of a protective layer on acomponent which is exposed to a high wear loading, which comprisesmixing at least one metallic material in powder form and a non-metallicoxide-dissolving fluxing agent in powder form, and adding a resin-likenon-corroding water soluble, stable binding agent to the materialmixture, wherein the material mixture with the fluxing agent and theresin-like water soluble binding agent is converted into a coatablepaste which after being applied to a member to be coated is hardened toform a hardened, wear resistant coating on said member having an exposedcoating surface, the said metallic material being at least one of aNi-B-Si base alloy, an alloy on a Ni-Cr-B-Si base, and a mixture of aNi-B-Si alloy and a Ni-Cr-B-Si base alloy.
 16. A process according toclaim 15 including the step of applying said coatable paste to a memberto form a hardened, wear resistant coating thereon.
 17. A processaccording to claim 15 wherein the material mixture is formed into astrip at a temperature below 141° C. and hardened.
 18. A processaccording to claim 17 wherein the material mixture is formed into astrip at a temperature between 80° and 140° C., and hardened.
 19. Aprocess according to claim 15 including mixing hard substances with thematerial mixture.
 20. A process according to claim 19 including the stepof coating the hard substances with a material selected from the groupconsisting of nickel and cobalt before mixing same with the materialmixture.
 21. A layer according to claim 2 wherein the material mixtureincludes water-soluble methacrylic acid esters as a binding agent forthe material mixture.
 22. A layer according to claim 13 includingtungsten melt carbides as hard substance additives.